Concrete testing apparatus



Oct. 6, 1931 O. H. HANSARD ET AL CONCRETE TESTING APPARATUS Filed Sept. 1. 1927 Q 7aiswrng.

Patented Oct. 6, 1931 UNITED STATES PATET OFFICE GREEN HARDIN HANSARD AND DONALD DAVID MCGUIRE, F NASHVILLE, TENNESSEE CONCRETE TESTING APPARATUS Application filed September This invention relates to apparatus for testing concrete and has for its principal object the provision of simple and easily portable means for readily and accurately determining the transverse strength of a specimen of concrete. Additional objects reside in the construction and arrangement of the apparatus hereinafter described in respect to one species of genus to which this invention more broadly pertains. Another species is illustrated and described in our copending application Serial No. 216,846 filed Sept. 1,

A recommended embodiment of the present species is shown in the accompanying drawings, in which:

Fig. 1 is a plan View of the improved apparatus with a specimen block of concrete in position for test;

Fig. 2 is a side elevation of the device shown in Fig. 1'; and Fig. 3 is an end elevation thereof, looking to the left of Figs. 1 and 2 the concrete having been removed.

The apparatus is Preferably mounted on a movable rectangular base 4 which may, if desired be mounted on wheels (not shown) to permit easy transportation. A horizontal platform .5 is mounted on legs 6 at one end of the base to support a rectangular specimen or beam of concrete 7 which may be fixedly secured on the platform by bars 8 and 9 disposed above the concrete and below the platform, respectively, and fastened by tie bolts 10. A portion of the concrete beam extends inwardly beyond the edge of the plat form and to this projecting end is attached a testing lever arm.

This lever preferably comprises a V-shaped metal frame consisting of similar I beams or arms 11 attached together at their outer ends and spaced at their inner ends by a transverse iiat metal strut 12 suitably bolted to the arms at ameasured distance from sai inner ends and also by a depending metal strap 13 also bolted to the arms with its inner edge at the inner ends of the arms and also lying close to the lnner edge of the platform 5 As clearly shown in the drawings the strut 1.2. rests upon the top of the con- 1, 1927. Serial No. 216,845.

crete beam near its projecting end and the strap 13 surrounds the beam and acts as a fulcrum at the edge of the platform when downward motion is imparted to the outer end of the lever arm.

At said outer end a rack l t bolted between the arm ends is preferably provided to support the upper strap or bail 15 of a dynamometer 16 of usual construction and operation. The dynamometer hangs in a vertical plane from the rack 1 1 and its lower operative strap 17 is attached to a cable 18 by a hook 19. The cable may be wound on a shaft or drum 20 mounted in bearing blocks 21 fixed to the base i, by means of a crank handle 22 operatlng through suitable gearing.

When the apparatus has been set up substantially in the manner shown in the drawlngs, the. crank 22 is operated to wind up the cable, thus exerting a downward .pull upon the dynamometer thereby depressing the outer end of the lever arm and consequently initiating a downward pressure at the strut 12 upon the projecting end of the concrete beam. When the breaking point is reached the concrete will fracture at the fulcrum point 23, and at that movement a reading of the dynamometer is taken. As the lever arm is then without support, bars 24- and 25, mounted at an appropriate height on brackets 26 and 27 respectively,-are preferably provided to pregent the lever arm from falling upon the The modulus of rupture of the concrete in pounds per square inch maybe then obtained mathematically'by well known formulze, after noting the. necessary weights and dimensions of the broken 05 section of concrete and of the lever arm. By utilizing the apparatus herein described, however, the computation is greatly simplified for the required weights and dimensions may be maintained constant, so that the only variable facd tor is the reading of the dynamometer.

Hence, after following the formula at the time of the initial test and calculating the resultant of the constants, the modulus of any succeeding test may be obtained by multiplying the constant factor by the reading .of he n rume t- A device constructed as above described is simple in construction, economical of manufacture, eas to manipulate and durable in use. It wil be understood, however, that the scope of this invention is not to be limited to the specific structual details herein illustrated, except as the invention is defined, in the following claims.

We claim:

1. Apparatus for testing concrete comprising means for holding a test piece horizontally, a horizontal lever engaging one end of the test piece held by said holding means, means connected with the free end of the lever for depressing the lever to break the test piece, and a measuring instrument associated with said last named means adapted to indicate the amount of force required to break the test piece.

2. Apparatus for testing concrete comprising means for holding a test piece horizontally, a horizontal lever attached at one end to one end of the test piece held by said holding means, means including a measuring instrument and a cable connected with the opposite end of said lever for depressing the lever to break the test piece.

3. Ap aratus for testing concrete comprising a p atform, means for securing a test piece of concrete upon said platform with one end of the piece projecting beyond the edge of the platform, a lever attached at one end to the said projecting end of the test piece, a measuring instrument connected with the opposite end of said lever, and means operative through said measuring instrument for depressing the lever to break the test piece.

4. Apparatus for testing concrete comprising a horizontal platform, means for securing a test piece of concrete upon said platform with one end of the test piece projecting beyond the edge of the platform, a lever attached at one end to the said projecting end of the test piece, a measuring instrument attached to the opposite end of the lever, a cable connected with said measuring instrument, and means for tensioning the cable to depress the lever and break the test piece.

5. Ap aratus for testing concrete comprising a p atform, means for securing a test piece of concrete upon said platform with one end of the test piece projecting beyond the edge of the platform, a lever having a strap at one end engagin the under side of the test piece adjacent the said edge of the platform and having a bar intermediate its ends engaging the upper side of said test piece near the end of its said projecting portion, means for depressing the free end of the lever to break the test piece, and a measuring instrument associated with said depressing means for indicating the amount of force required to break the test piece.

6. Apparatus for testing concrete comprising a platform, means for securing a test piece of concrete upon said platform with one end of the test piece projecting beyond the edge of the platform, a lever extending over the projecting end of the test piece and having its free outer end in line with the test piece and distant from the end thereof, the inner end of the lever having a strap passing under the projecting end of the test piece and engaging thebottom side thereof adjacent the said edge of the platform, a cross bar intermediate the ends of the lever engaging the upper side of said test ,piece near theouter-endof its projecting portion,

means for depressing the free end of the test piece, and a measuring instrumentassociated with said depressing means adapted to indicate the amount of force required to break the test piece.

7. Apparatus for testing concrete comprising a horizontal platform, means for securing a test piece of concrete upon said platform with one end of the test piece projecting beyond the edge of the platform, a horizontal lever extending over the projecting end of the test piece and having its free outer end in line with the test piece and distant from the projecting end thereof, a strap fixed to the inner end of the lever passing under the projecting portion of the test piece and engaging the bottom side thereof adjacent the said ed e of the platform, a cross bar fixed to the Bottom of the lever intermediate its ends, said cross bar engaging the upper side of the test piece near the end of its projecting portion, a measuring instrument attached to the free end of the lever, a cable connected with said measuring instrument, and means for tensioning said cable to depress the lever and break the test piece.

8. Apparatus for testing concrete comprising a horizontal platform, means for securing a test piece of concrete upon said platform with one end of the test piece projecting beyond the edge of the platform, a horizontal lever extending over the projecting end of the test piece and having its free outer end in line with the test piece and distant from the projecting end thereof, a strap fixed to the inner end of the lever passing under the projecting portion of the test piece and engaging the bottom side thereof adjacent the said edge of the platform, a cross bar fixed to the bottom of the lever intermediate its ends said cross bar engaging the upper side of the test piece near the end of its projecting portion a dynamometer having one bail attached to the free end of the lever and another bail connected to a cable, and means for tensioning the cable to depress the lever and break the test piece.

In testimony whereof we aflix our signa- 

